COMPRESSED-AIR GENERATOR COMPRISING AN INJECTOR AND A PRESSURE TANK

Abstract: In a compressed-air generator comprising an injector (5) driven by circulating liquid delivered by a pump (4) so as to draw atmospheric air (8a) into the lower part of a reservoir tank (2), in which the air bubbles (8b) rise and collect in the form of compressed air (8p) in the top of the tank, while the pumping liquid (12) is returned (13) to the pump (4), the main novel feature is that the pump (4) and the injector (5) constitute parts of an independent, self-contained unit (1), such as a high-pressure cleaner, adapted to be connected to or disconnected from the reservoir tank (2) by means of easily operated couplings (3i, 3r). With this arrangement, a high-pressure cleaner may be converted into a compressed-air generator by adding an auxiliary component in the form of the reservoir tank (2), thus obviating the need for purchasing a separate compressor arrangement.

Description: COMPRESSED-AIR GENERATOR COMPRISING AN INJECTOR AND A PRES¬ SURE TANK. TECHNICAL FIELD The present invention relates to a compressed-air generator of the kind set forth in the preamble of claim 1. BACKGROUND ART Equipment of the kind referred to above is known from US-A-899820, US-A-2702664, GB-A-2042080 and WO-A-87/01770. In the apparatus according the above-mentioned publications, every component of each apparatus solely serves to fulfil the pumping function of the apparatus itself. Thus, the apparatus according to the three first-mentioned publications constitute units being permanently assembled for the purpose, whilst the technology according to the WO-publication espe¬ cially relates to the functional optimization of the injector used for the pumping function. Further, these publications do not mention the use of any components of the equipment for other independent functions than the pumping function itself. Now, in recent years, high-pressure cleaners have become highly estimated as tools for cleaning surfaces within both the manufacturing industry and the building industry, as well as in agriculture, the manual crafts and various ser¬ vices. The cleaning process may constitute ordinary clea¬ ning, or it may - which is frequently the case - be carried out in preparation to further finishing work. All depending of the nature of the work to be carried out by the high-pressure cleaner, it is possible to effect a simultaneous addition of chemicals or abrasives in dosable quantities to the mains water, with which the high-pressure cleaner normally operates. The addition is carried out in a mixing element, being a component of the high-pressure clea- ner and constituting a flow element with pumping effect, that may well be in the form of an injector, e.g. comprising a Venturi passage. If the high-pressure cleaner is used to prepare a workpiece or a surface of same for further finishing work, the latter is frequently associated with the use of compressed-air- driven tools and/or spray guns for applying paint of some kind. Through the appearance of smaller and lighter high-pressure cleaners for home use, the use of high-pressure cleaning is now also spreading to the large market for do-it-yourself activities. Thus, a substantial and steadily growing number of high-pressure cleaners may now already be found in private households. The widespread use of high-pressure cleaning is relatively recent. Among the consumers on the do-it-yourself market mentioned above, there is, however, also an extensive need for access to compressed air in the private households for various applications, e.g. spanning from inflating rubber tires to supplying driving power both to the tools and spray guns mentioned above and to light compressed-air tools in general. The average household will, however, consider a conventional motor compressor, even with a capacity satisfying lesser needs, as relatively expensive, due to the - after all - limited applicability. For this reason, a substantial pro- portion of the buyers in the do-it-yourself market will only accept expenses for the purchase of either a high-pres- sure cleaner or an air compressor, having to do without the apparatus not having been purchased, and in the case of need having to hire such apparatus or substitute for it other, less effective tools or other, less ideal processes. To this may be added that the conventional air compressor, due to its great weight, and even when provided with wheels is rather unmanageable when it is to be transported to the place of work and back. Further, it occupies space, both during transportation and when being stored in the inopera¬ tive state. DISCLOSURE OF THE INVENTION On this background, it is the object of the present invention to provide a compressed-air generator of the kind referred to initially, with which the disadvantages referred to above may be overcome in a new and surprising manner, and this object is achieved by means of a compressed-air generator according to the invention exhibiting the features set forth in the characterizing clause of claim 1. With this arrange¬ ment, the high-pressure cleaner with its associated injector is used, by being connected to a compressed-air tank, to compress air and inject it into the tank, from which the compressed air then may be drawn off in the conventional manner. Thus, what is new and characteristic for the compressed-air generator according to the present invention is that the liquid pump and the injector belong to an apparatus with a separate, independent function, and that it is possible, when need arises, to form the compressed-air generator merely by connecting said apparatus with a pressure tank in the form of a loose reservoir tank. Surprisingly with this arrangement, a series of new advan¬ tages, unknown prior to the present invention, are achieved. Thus, with the compressed-air generator according to the invention, the conventional compressed-air equipment with its heavy, bulky and expensive compressor, motor, mains connections and hoses may be omitted with concomitant eco¬ nomical advantage, whereas according to a preferred embodi¬ ment of the compressed-air generator according to the inven- tion, the hoses and hose connectors associated with the high-pressure cleaner are constructed in a manner allowing them to be used in connection with the compressed-air tank. Thus, as will be evident from the above, the compressed-air generator according to the invention is set up according to need when compressed air is required, by merely adding to the high-pressure cleaner a light, handy and inexpensive auxiliary equipment component in the form of the special portable reservoir tank. When there is no longer a need for compressed air, the reservoir tank is disconnected, after which the high-pressure cleaner is immediately ready for use in its independent function of high-pressure cleaning. In this manner, the compressed-air generator according to the present invention provides both present and future owners of high-pressure cleaners access to compressed air in an easy, space-saving, handy and inexpensive manner, that would otherwise not be available to them. Further: with the present invention, for each high-pressure cleaner previously leading to the purchase of an air compres¬ sor, it is possible to achieve hitherto unattainable savings in resources, viz. those relating to the manufacturing of the motor, the compressor and the connecting elements, with the consequent environmental advantages. BRIEF DESCRIPTION OF THE DRAWING In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiment of a compressed-air generator according to the invention shown in the drawing in which the references listed in the list of parts at the end of this description have been used. DESCRIPTION OF THE PREFERRED EMBODIMENT The compressed-air generator according to the invention is formed by coupling together the apparatus 1, in this case being a high-pressure cleaner 1, and the reservoir tank 2, which is a pressure tank, by means of coupling members 3i and 3r, and the generator functions as follows: The pump 4 of the high-pressure cleaner 1 forces a pumping liquid, notably ordinary mains water, through the injector 5 of the high-pressure cleaner 1. The high flow velocity of the pumping water determined by the pump 4 produces in the usual manner a substantial partial vacuum in the Venturi passage of the injector 5, hence also in the side bore 7 adapted for supplying additives during high-pressure cleaning operations, so that atmospheric air 8a is aspirated through the non-return valve 9. The atmospheric air 8a is entrained by the pumping water, compressed during the passage through the compression section 10 of the injector 5, and is injected together with the water through the delivery tube or hose 11 and the input coupling member 3i into the reservoir tank 2. In the latter, the air separates out from the water in the form of air bubbles 8b and collects as compressed air 8p in the upper part of the tank 2, while the pumping water 12 collects in the bottom of the tank 2, from where it flows through the return coupling member 3r and the return tube or hose 13 back to the inlet side of the pump 4. The com¬ pressed air 8p so formed may be drawn off through the draw- ing-off tube or hose 14. Thus, the compressed-air generator operates with a constant quantity of circulating pumping water 12 and under the static compressor pressure at any time prevailing in the reservoir tank 2. The latter is pro¬ vided with a safety valve 15 and a pressure gauge 16 showing the compressor pressure. In a preferred embodiment of the compressed-air generator, the reservoir tank 2 is provided with a filter 17 situated above the upper level of the pumping liquid in the reservoir tank 2, said filter filtering off and retaining suspended water particles and droplets from the compressed air 8p. The coupling members 3i and 3r shown, as well as any coupling members not shown, may be in the form of spanner-operable threaded couplings or - in a preferred embodiment of the in¬ vention - in the form of manually operable quick-action couplings facilitating the operation and re-arrangement of both the high-pressure cleaner 1 and the compressed-air generator. According to a preferred embodiment, the coupling members 3i and 3r are of the type adapted to close the connection to the reservoir tank 2 before connection or disconnection of the hoses 11 and 13, either automatically or by a simple manipulation. This makes it possible to join or separate the high-pressure cleaner 1 and the reservoir tank 2 without loss of pumping water 12 or compressed air 8p. The connecting hoses 11, 13 and 18 of the high-pressure cleaner 1, as well as any extension hoses not shown, may advantageously be fully interchangeable with each other and with the connecting hoses 11, 13, 14 and 18 of the com¬ pressed-air generator, as well as with any of the latter's connecting and extension hoses not shown. In order to further facilitate the handling of both the high-pressure cleaner 1 and the compressed-air generator as a whole, the apparatus components may be provided with one or more coupling members and/or switching valves in such an arrangement, that the reservoir tank 2 constitutes a concep¬ tually functionally completely integrated auxiliary equip¬ ment for the high-pressure cleaner 1. Thus, even though the feed apparatus 1 is preferably a high-pressure cleaner 1, it will be obvious that any kind of apparatus 1 comprising at least a liquid pump 4, the pressure side of which may be connected to a flow element 5 with pumping effect constituting part of the apparatus 1, said apparatus further having a second independent function, may be contemplated as used to form a compressed-air gene¬ rator according to the invention in connection with a reser¬ voir tank 2. LIST OF PARTS 1 High-pressure cleaner 2 Reservoir tank 3i Input coupling member 3r Return coupling member 4 Pump 5 Injector 6 Venturi passage 7 Side bore 8a Atmospheric air 8b Air bubbles 8p Compressed air 9 Non-return valve 10 Compression section 11 Delivery tube/delivery hose 12 Pumping water 13 Return tube/return hose 14 Drawing-off tube/drawing-off hose 15 Safety valve 16 Pressure gauge 17 Filter 18 Connecting tube/connecting hose

Claims: CLAIMS . 1. Compressed-air generator comprising a liquid pump (4), an injector (5) and a reservoir tank (2) in the form of a pressure tank, said elements being connected in said sequence to form a flow circuit, in which atmospheric air (8a) is compressed so as to form compressed air (8p) by being drawn into a flow element with inherent pumping effect in the form of an injector (5), preferably having a Venturi passage, by a pumping-liquid current circulating in said flow circuit, and by being injected together with said pum¬ ping liquid into the reservoir tank (2), from which the pumping liquid via a return conduit (13) flows back to the liquid pump (4) driving the circulating pumping-liquid cur- rent, while in the reservoir tank (2), the air (8b) having thus been injected is separated from the pumping liquid and collected (8p) in the upper part of the tank (2), from where it may be drawn off (14) in the form of compressed air, characterized in that said liquid pump (4) and said injector (5) constitute components of an independent apparatus (1) with a second, independent function, notably a high-pressure cleaner (1), and that said independent apparatus (1) and the reservoir tank (2) together constitute the com¬ pressed-air generator. 2. Compressed-air generator according to claim 1, characterized in that the high-pressure cleaner (1) according to need may be connected to and disconnected from the reser¬ voir tank (2) by means of simple coupling members (3i, 3r), so that the two in their interconnected state constitute the compressed-air generator. 3. Compressed-air generator according to claim 1 or 2, characterized in that the reservoir tank (2) comprises a filter (11) situated above the level of the surface of the pumping liquid (12) and the compressed air (8p). 4. Compressed-air generator according to any one or any of the claims 1-3, characterized in that the coupling members (3i, 3r) are constituted by manually operable quick-action couplings. 5. Compressed-air generator according to any one or any of the claims 1-4, characterized in that the coupling members (3i, 3r) are of a type closing the reservoir tank (2) before the hoses (11, 13) can be connected or discon¬ nected, either automatically or by simple manipulation. 6. Compressed-air generator according to any one or any of the claims 1-5, characterized in that all hoses (11, 13, 14, 18 etc. ) and hose connections are interchangeable and adapted for use between the high-pressure cleaner (1) and the compressed-air generator. 7. Compressed-air generator according to any one or any of the claims 1-6, characterized in that the high-pres¬ sure cleaner (1) and the reservoir tank (2) are provided with such further interconnecting means and/or valve means, that in practical operation, the reservoir tank constitutes a conceptually functionally completely integrated auxiliary equipment for the high-pressure cleaner.

Inventors: JENSEN JOERN GUNNAR, JENSEN, JOERN, GUNNAR
Applicants: JENSEN JOERN GUNNAR, KEW IND AS, JENSEN, JOERN, GUNNAR, KEW INDUSTRI A/S
Application year: 1994
Main classification: F04B23
IPC codes: B08B3, F04B23, F04F5